Optical fibers are used extensively in displacement sensor technology. One method of obtaining a displacement measurement is to attach a first optical fiber cable to the object whose displacement is to be sensed while a second optical fiber cable, whose end is aligned with the end of the first optical fiber cable, is held stationary. One of the optical fiber cables has a light source attached to its other end while the other of the optical fiber cables has a light receiver attached to its other end. When the object is displaced, the light coupling between the two optical fiber cables changes, thus changing the amount of light received by the light receiver from the light source.
An inherent problem associated with the foregoing optical fiber sensor apparatus is the alignment of the ends of the optical fiber cables relative to one another along the three co-ordinate axes. When measured displacement occurs along the X axis, sensitivity of the sensor depends on the relative position of the ends of the optical fiber cables along this axis. If the ends of the optical fiber cables are misaligned along this axis by more than the diameter of the cables, no signal is transmitted through the cables. The resulting sensitivity of the sensor also depends on misalignment of the ends of the optical fiber cables along the Y axis. In addition, the intensity of the light transmitted depends on the closeness of the ends of the optical fiber cables, i.e., the alignment of the cables along the Z axis.
Because of the foregoing, it has become desirable to develop apparatus for aligning the ends of optical fiber cables which permits displacement along only one co-ordinate axis and which has a high degree of sensitivity to such displacement.